Aluminum alloys have been widely used in semiconductor plasma etching tools over the past thirty years. For example, anodized aluminum has unique properties such as high corrosion resistance, high surface micro-hardness, high plasma resistance, low cost, and large manufacture capabilities when compared to bare aluminum.
However, poor anodization and/or coating leads to a short lifetime, severe corrosion, high particles and defects, and high metal contamination of plasma etched wafers. To test the corrosion resistance of such parts, bubble testing, such as HCl bubble testing can be used. Commonly assigned U.S. Patent Application Publication 2008/0241517 discloses details of HCl bubble testing. When anodization fails, HCl and/or other acids react with aluminum and/or steel to generate hydrogen bubbles. Thus, the appearance of hydrogen bubbles can be used to determine the time of failure or the bubble time. However, the bubble test can be somewhat limited since human monitoring is required for the duration of the test.
Thus, an automated bubble detection apparatus, which requires minimal human intervention, is repeatable and cost effective is desirable.